This turned out to be a temporary glitch with GMail, but still an interesting one. I accidentally noticed it since all my email from my GMail account is routed to a “google@” address on a domain I use exclusively for email. For a few hours today, all emails sent from my GMail account to a “google” account on any of my domains were being bounced back. For example, sending an email to google@broobles.com bounced back with the following message:

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This is an automatically generated Delivery Status Notification
Delivery to the following recipient failed permanently:

Sending an email to google1@broobles.com a few seconds later worked just fine. I was able to repeat this several times during the past few hours, however the issue now seems to be resolved. Obviously, I couldn’t perform too many tests, but I did try a few involving “google” and “gmail” and the only one that consistently failed was google@broobles.com.

I wonder what type of DNS server is used internally by GMail and why it had problems extracting a domain from an email address addressed to a “google” account on a valid domain.